EVOLUTION OF A FISHERY CONDITION ASSESSMENT PART II: WHAT IS CONDITION?

Road dips are a fish’s best friend.- Ken Roby

As I wrote about previously, the first Technical Advisory Team (TAT) Meeting of the Upper Feather River Basin-Wide Native Fish Assessment and Improvement Strategy took place on April 19th, 2016 where we discussed next steps in the  Assessment, namely how to assess overall condition of the watershed. Defining condition will help inform our end goals, which are to prioritize locations in the Upper Feather River Watershed for 1) conservation and 2) restoration.

Identifying the condition of a given area of the watershed will determine if the area should be slated for conservation, restoration, or not incorporated into project work. The areas with excellent native fisheries should be prioritized for conservation, i.e. protection, to ensure that they stay excellent. The areas that are more marginal but could be improved with some work should be targeted for, yes, RESTORATION!

So, since the TAT meeting, my project advisors and I have worked to synthesize the information generated in order to develop a framework for assessing the condition of different areas of the watershed. We started by developing a list of factors, or indicators, that cumulatively characterize the condition of a particular watershed and its fishery.

We know that a good indicator must fit a number of important criteria, namely:

  • It must have a close relationship to fish habitat or distribution
  • It must be measurable
  • It must have an available data source
  • It should have Basin-wide coverage
  • It should have documented effect
 A massive road failure in Umpqua National Forest. Credit: USFS

A massive road failure in Umpqua National Forest. Credit: USFS

For example, let’s say we are interested in potentially using sediment as a condition indicator. We know that an excess of fine sediment is harmful to fish, with high amounts able to smother viable spawning gravels and even kill live fish like the juveniles produced by the Lake Almanor rainbow trout shown below (note that these fish were not actually harmed by any human activities). There are established methods of measuring both the natural dynamics of and anthropogenic influence on the sediment regime*, such natural soil erosion rates or road densities (which contribute to erosion). We also have very good data sources; soil characteristics have been mapped since the late 19th and early 20th century in United States Department of Agriculture initiatives related to food security and national productivity, including in our national forests! So, we therefore also know that we have Basin-wide coverage for data sources related to sediment. Additionally, there are many studies that have meaningfully documented the impacts of excessive sediment on water quality, and thus fisheries.

 Well-designed and regularly placed dips on unpaved roads can prevent the accumulation of runoff that results in road failure. Credit: UN FAO.

Well-designed and regularly placed dips on unpaved roads can prevent the accumulation of runoff that results in road failure. Credit: UN FAO.

So, it is safe to say that sediment is one good indicator for describing watershed condition. But, it is only one. There a numerous other factors that we know affect fishery condition that we must identify and include as condition indicators. These factors may be abiotic, that is completely physical phenomena like sediment or nutrients. Or they could be biotic, or living, such as the pathogens or introduced competitors that affect native fish.

Currently, the project facilitators have developed a working framework with a set of indicators that we believe is a good starting point for a meaningful assessment that reflects actual conditions in the Basin. This draft framework is under review by the Core Group of our Technical Advisory Team and will be finalized for work to begin in the coming weeks.

* “Sediment regime” refers broadly to the rate of sediment production, transport, and delivery; how much and where it comes from, where it goes, and where it ends up.